commu.c

《C语言精彩编程百例》附书源码

# include <stdio.h>
# include <stdlib.h>

# define MAX 100

struct addr
{
	char name[20];
	char street[40];
	char city[20];
	char state[4];
	unsigned long zip;
} addr_list[MAX];

void init_list(void);
void enter(void);
void dele(void);
void list(void);
void save(void);
void load(void);
int menu_select(void);
int find_free(void);

void main()
{
	char choice;

	init_list();
	for( ; ; )
	{
		choice = menu_select();
		switch(choice)
		{
		case 1: enter();
			    break;
		case 2: dele();
			    break;
		case 3: list();
			    break;
		case 4: save();
				break;
		case 5: load();
				break;
		case 6: exit(0);
		}
	}
}

void init_list(void)
{
	register int t;

	for(t=0; t<MAX; t++)
		addr_list[t].name[0] = '\0';
}

void enter(void)
{
	int slot;
	char str[80];
	
	slot = find_free();

	if(slot == -1)
		printf("\nList Full");

	printf("Enter name: ");
	gets(addr_list[slot].name);

	printf("Enter street: ");
	gets(addr_list[slot].street);

	printf("Enter city: ");
	gets(addr_list[slot].city);

	printf("Enter state: ");
	gets(addr_list[slot].state);

	printf("Enter zip: ");
	gets(str);
	addr_list[slot].zip = strtoul(str, '\0', 10);
}

void dele(void)
{
	register int slot;
	char str[80];

	printf("Enter record #: ");
	gets(str);
	slot = atoi(str);

	if(slot>=0 && slot<MAX)
		addr_list[slot].name[0] = '\0';
}

void list(void)
{
	register int t;

	for(t=0; t<MAX; t++)
	{
		if(addr_list[t].name[0])
		{
			printf("%s\n", addr_list[t].name);
			printf("%s\n", addr_list[t].street);
			printf("%s\n", addr_list[t].city);
			printf("%s\n", addr_list[t].state);
			printf("%s\n\n", addr_list[t].zip);
		}
	}
	printf("\n\n");
}

void save(void)
{
	FILE *fp;
	register int i;

	if((fp=fopen("maillist", "wb"))==NULL)
		printf("Cannot open file.\n");

	for(i=0; i<MAX; i++)
		if(*addr_list[i].name)
			if(fwrite(&addr_list[i], sizeof(struct addr), 1, fp)!=1)
				printf("File write error.\n");

	fclose(fp);
}

void load(void)
{
	FILE *fp;
	register int i;

	if((fp=fopen("maillist", "rb"))==NULL)
		printf("Cannot open file.\n");

    init_list();
	for(i=0; i<MAX; i++)
		if(fread(&addr_list[i], sizeof(struct addr), 1, fp)!=1)
		{
			if(feof(fp))
				break;
			printf("File read error.\n");
		}

	fclose(fp);
}

int menu_select(void)
{
	char str[80];
	int c;

	printf("1. Enter a name\n");
	printf("2. Delete a name\n");
	printf("3. List the file\n");
	printf("4. Save the file\n");
	printf("5. Load the file\n");
	printf("6. Quit\n");

	do{
		printf("\nEnter your choice: ");
		gets(str);
		c = atoi(str);
	} while(c<0 || c>6);
	
	return c;
}

int find_free(void)
{
	register int t;

	for(t=0; addr_list[t].name[0]&&t<MAX; t++);

	if(t==MAX) 
		return -1;

	return t;
}